Published 4:00 am, Wednesday, March 6, 1996

A San Francisco sting operation yesterday closed in on three Tenderloin businessmen who authorities say were trying to bribe a police officer into protecting their illegal gambling activities.

After a nearly five-month investigation by San Francisco police, more than two dozen state and local officials armed with search warrants fanned out over 24 locations in San Francisco, San Mateo, Alameda and Santa Clara counties. Officers were looking for illegal gaming machines -- namely, video poker games -- that authorities believe the three men assembled and then distributed throughout the Bay Area.

Jay Nguyen, 31, was arrested yesterday in the Tenderloin and booked on six counts of bribery and one count of conspiracy to obstruct justice, said District Attorney Terence Hallinan.

Arrest warrants were also issued for 65-year-old Nam Thanh and 37-year-old Lan Trang, but police were still searching for them. Thanh and Trang have each been charged with one count of conspiracy to obstruct justice, said Assistant District Attorney Jerry Coleman who heads the office's special prosecution unit.

The three men are accused of giving a San Francisco vice inspector $26,000 over a period of five months in exchange for the return of illegal gaming machines that had been seized from their businesses and for protection against future raids, Hallinan said.

"Attempting to corrupt law enforcement officials is the most heinous kind of offense," he said.

Coleman said that according to a court affidavit, the three men approached a vice inspector late last year after their businesses were targeted for several raids after police were tipped that the men were running illegal gambling operations. The operations were allegedly run out of various Ellis Street restaurants, bars and retail shops that the men are connected with, Coleman said the affidavit states.

The machines typically generate "thousands of dollars a day" for the operators, Coleman said information in the affidavit states.

The vice inspector -- Robert Guinan -- alerted his commanding officers and the district attorney's office that the offer had been made. Between October 4 and February 27, six transactions were made and captured by a hidden police video camera, Coleman said the affidavit states. At one point the men even gave Guinan a receipt -- a gesture Hallinan called "pretty arrogant."

Hallinan said his office believes the three men are the key culprits in the case but said that the investigation is continuing.

Nguyen is being held on $5,000 bail. He is expected to be arraigned on the charges soon.